Page 5 - Curriculum Visions Dynamic Book

most common uses we can think of for lead – for pencils – is not actually lead. Pencil “lead” is made from a form of carbon called graphite. In fact, if a pencil contained real lead, it would be very
heavy to pick up, because lead is one of the heaviest metals on Earth.
Tin
The chemical symbol for tin is Sn, which comes from the Latin word stannum. It has many properties similar to lead;
for example, it is a soft, weak metal and unreactive like lead. Tin is found associated with copper and, like zinc, it has a low melting point. Tin was probably first used by ancient
civilisations accidentally combined with copper. In this way they discovered bronze, the metal that gave its name to the period of
ancient history called the Bronze Age.
Tin metal quickly develops an invisible protective coating
when exposed to air. For this reason it has been used as a plating for protecting metals such as iron. But, because tin
is less reactive than iron, tin is not
an ideal material for protecting steel, and tin plate has been
replaced by aluminium in many canning applications.
Tin is mainly found in alloys, including solders used in electronic
circuits. Its other important role is as a liquid bed for the
production of the sheet glass used for window panes, known as
float glass.
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